The invention relates to the field of photonic bandgap crystals, and in particular to forming compact and simple devices using photonic bandgap crystals.
A photonic bandgap crystal (PBG) has been widely investigated recently due to its unique property. It is well known that by employing a PBG structure, high reflection is easily achieved by sandwiching a defect layer between two PBG stack layers. It is possible to form a cavity mode with a high Q (quality factor) using a PBG structure, where a specific wavelength can be transmitted and other wavelengths are reflected. There have been various optical devices formed using PBG structures in integrated optics, but most of these devices are limited to two-dimensional optical waveguide structures by which light can be guided along a waveguide or optical fiber.